In wireless communication systems, radio transmitters may transmit and/or receive radio frequency (RF) signals through one or more antennas. Some wireless communication devices may include multiple antennas, for example two or more antennas. Those wireless communication devices may include multiple-input-multiple-output (MIMO) modulation and/or coding to control receiving and transmitting of RF signals through the multiple antennas.
MIMO system may include a diversity MIMO system or multiplexing MIMO system. In the diversity MIMO system incoming bits may be coded over multiple transmitting antennas to gain sensitivity by exploiting multi path propagation channel property. In the multiplexing MIMO system the multiple transmitting antennas may be used to convey multiple modulated streams of data. In this MIMO system spatial decoding methods may be used to decode the modulated data streams.
A MIMO system may use orthogonal frequency division multiplexing (OFDM) systems coding for multiplexing or diversity evenly on the entire OFDM sub-carriers symbol without any discrimination. A failure to multiplex in at least some bits of the OFDM sub-carriers symbol may cause all bits of the OFSM sub-carriers symbol to be in error.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.